GB2417193A

GB2417193A - Cooking vessel with scraper blades

Info

Publication number: GB2417193A
Application number: GB0521386A
Authority: GB
Inventors: David Alan Norris
Original assignee: DC Norris and Co Engineering Ltd
Current assignee: DC Norris and Co Engineering Ltd
Priority date: 2002-12-17
Filing date: 2003-12-16
Publication date: 2006-02-22
Anticipated expiration: 2023-12-16
Also published as: GB2417192A; GB2406040B; GB0521386D0; GB0521385D0; GB2417193C; GB2406040C; GB2406040A; GB0329157D0; GB2417193B; GB2417192B; GB2417192C; GB2417192C2

Abstract

A cooking vessel has a rotary agitator is provided to stir or agitate the vessel contents provided with scraper blades for scraping the inner surface of the vessel. Each blade is in the form of a one-piece plastics member (28) having trunnions 40 received in openings in a support 30. The trunnions and the openings in the supports are shaped so as to cooperate and allow the blade a restricted amount of angular movement towards and away from the inner surface of the vessel. The shapes of the blades and their supports also facilities cleaning.

Description

-1- 2417193

IMPROVEMENTS IN COOKING VESSELS

This invention relates to cooking vessels for flowable food products.

It is known for a flowable food product intended for subsequent reheating to be pre-cooked in a kettle including a dished cooking vessel arranged within a steam heated jacket. A rotary agitator is provided for circulating the contents of the vessel and causing them to be brought into contact with the hot inner surface of the vessel. The known design of a kettle has been found to be very satisfactory when used to pre-cook many types of food products used for convenience foods, and in particular soups and sauces.

It is desirable to provide an arrangement for scraping the inner surface of the vessel to prevent solid or semi-solid food product adhering to it and becoming over- cooked. The scrapers used for this purpose suffer from wear and must be replaced at intervals. To reduce the frequency of scraper replacement, the blades of the scrapers are mounted for adjustment relative to the wall of the vessel so as to accommodate wear as it takes place. Each of the scraper blades is preferably mounted in a support which permits a limited degree of movement towards and away from the vessel wall. The conventional arrangements used for mounting the blades employ fittings which tend to accumulate particles of food product which may harbour bacteria and are difficult to clean.

According to the invention there is provided a cooking vessel in which a rotary agitator is provided to stir or agitate the vessel contents, the agitator being provided with a plurality of scraper blades each in the form of a one-piece plastics member, having trunnions received in openings in a support, the trunnions and the openings in the support being shaped so as to cooperate and allow the blade a restricted amount of angular movement towards and away from the inner surface of the vessel. This arrangement avoids traps for bacteria and is easy to clean, so ensuring a high level of hygiene.

Preferably each of the trunnions has a peripheral surface defined by a pair of semi- cylindrical portions joined by planar surfaces and the openings in the support are generally rectangular in shape with curvilinear corners. This arrangement serves to - 2- restrict the movement of the blade while avoiding traps for bacteria.

The scraper blades preferably have dished or shovel-like constructions so as to promote flow of food product away from the vessel wall as scraping takes place.

Herein, unless the context otherwise requires, the expression "agitator" comprehends devices which agitate the food product by a reciprocal angular movement, and also devices which stir the food product by rotating continuously in a single direction.

In the drawings: Figure 1 is a plan view of a cooking kettle incorporating scraper blades in accordance with the invention; Figure 2 is a radial section through the kettle taken on the line 2-2 in Figure 1; Figure 3 is a radial section taken on the line 3-3 in Figure 1; Figure 4 is a perspective view of a scraper blade assembly used in the kettle; Figure 5 shows to an enlarged scale the detail H in Figure 3 to illustrate in section the scraper blade assembly, showing an unworn blade positioned for scraping the inner surface of the vessel wall during forward movement of the agitator; Figure 6 is a side view of a scraper blade in its mid-position; Figure 7 is a view similar to Figure 6 but showing how the blade may tilt rearwardly; Figure 8 is a view similar to Figure 3, but showing the blade in its scraping position following wear of the blade tip; Figure 9 is a longitudinal section through the blade taken on line 9-9 in Figure 10 to indicate the consequences of wear of the blade tip; and - 3- Figure 9A is a plan view of the blade; Referring to Figures 1 to 3 of the drawings, which are in a diagrammatic form for the purposes of illustration, a kettle incorporates a cooking vessel 2 and a supporting frame 4 having legs 6. The vessel has a hemispherical lower portion or bowl 10 surmounted by a cylindrical upper portion 12. In use, the bowl is filled with food product.

Water or other liquid product may enter the vessel through a pipe 14, and solid or semi- solid product may be introduced through an inlet in the cover of the vessel. A reversible electric motor 16 is mounted on a superstructure 18 for driving in rotation the shaft 20 of an agitator or stirrer incorporating an arcuate bar 22. The vessel has a removable cover (not shown) and a jacket through which steam may be passed so as to raise the temperature of the surface of the vessel to substantially 180 TIC. After cooking, the food product is drawn off through an outlet 24. A pneumatic cylinder 26 is mounted on the frame for tilting the superstructure away from the kettle and so lifting the agitator out of the bowl.

The arcuate bar 22 is concentric with the inner surface of the bowl and conveniently formed from a metal tube secured at its mid-point to the lower end of the drive shaft. The bar 22 thereby has two limbs of equal length which extend away from the point of connection of the bar 22 with the drive shaft. Each limb of the bar 22 extends through an angle exceeding 90 degrees. The drive shaft and agitator may be arranged to rotate continuously in what may be regarded as a forward direction indicated by arrow A in Figure 1, such rotation taking place about an axis arranged at an angle of approximately 30 degrees relative to the vertical. With this arrangement the agitator tends to cause the food product to follow a rising and falling path within the bowl. Plastic scraper blades 28 fitted to the bar 22 are provided to scrape over the surface of the bowl during rotation of the agitator In the forward direction and prevent food product from adhering to the surface and becoming overheated. A single one of the scraper blades is shown in Figures 5 to 10. Each scraper blade is carried by a stirrup 30 welded to the bar 22 and is of a dished or shovel-like shape for guiding scraped- off food product away from the bowl wall. The limbs 48 of the stirrup may be formed from spring steel to enable them to be sprung apart, or may be of more rigid in construction and forced apart by a tool. - 4-

Although spaced from one another, the blades cooperate to scrape the entire area of the hemispherical bowl surface covered in food product during each revolution of the agitator in the forward direction.

Each of the scraper blades is moulded from nylon or other suitable plastics material and is defined by a bottom wall 32 terminating at its free edge in a scraper tip 34 and by side and end walls, 36 and 38, respectively. The inner surface of the bottom wall merges into the inner surface of the end wall and each of the side walls by way of concavely curved surfaces 37 and 39. The tip 34 extends beyond the side walls 36 and is curved in plan to conform to the curvature of the bowl, as seen best from Figure 10.

The tip has a chamfer 35 so as to present a sharp edge. Projecting from each side wall is an integral trunnion 40 having opposite straight sides 42 joined by semi-circular sides 44. The trunnions of each blade are in alignment with each other and received in openings 46 of generally rectangular shape with rounded corners formed by bending the ends of the limbs 48 of the stirrup to form loops. Alternatively, the stirrup may be formed other than by bending so as to have shaped openings 46. Cooperation of the trunnions with the openings 46 allows each scraper blade to pivot between the extreme positions shown in Figures 7 and 8, but not beyond these positions.

The rounded shapes of the trunnions and the openings in which they are received ensure ease of cleaning after use. Similarly the concave curvatures between the walls of the scraper blade also render the scraper easier to clean.

When the agitator is rotated in the forward direction A, the pressure of food product against the inner side of the bottom wall of each scraper blade biases the tip of each scraper blade so that it bears against the inner surface of the bowl. Food product scraped from the surface of the bowl is swirled away from the surface towards the centre of the bowl by the side and end walls of the blade. The shape of the blade serves to propel food product more positively towards the centre of the vessel than the blades known hitherto, the effect being enhanced by the shape of surfaces 37 and 39.

It will be noticed from Figure 2 that the blades nearest the ends of the bar 22 will emerge from the food product when in the position shown at X. In this "high" position, the blade tends to fall back on itself in the direction of arrow D indicated in Figure 5 into - 5- the position shown in Figure 7. Similarly, if the agitator is rotated in the reverse direction indicated by arrow B. the pressure of food product against the underside of the bottom wall 32 may tilt the scraper blade in the direction indicated by arrow D so that the scraper blade moves into the Figure 7 position. Cooperation of the trunnions 40 with the edges of openings 46 prevents further tilting of the scraper blade in this direction and so avoids the blade tipping completely over.

When unworn, the scraper blade occupies the mid position shown in Figures 5 and 6 during scraping. As wear of the blade tip takes place, the scraper blade moves progressively in direction of the arrow C indicated in Figure 5 towards the limiting position shown in Figure 8 at which point the scraper blade must be renewed. As shown in Figure 9, the tip 34 wears in such a way as to retain a sharp edge 50 and continues to scrape the bowl effectively.

To replace the blades the agitator is removed from the vessel by extending the cylinder 26. The worn scraper blades may be removed by forcing the limbs of the stirrups apart to release the journals on the blades, new scraper blades inserted in their place, and the limbs returned to their original position.

The means of heating the cooking vessel and the internal shape of the vessel, as well as the construction of the agitator, may be different from those described above.

Also, alternative arrangements may be employed for supporting the scraper blades.

Thus, for example, the trunnions and openings in which they are received may be of circular cross-section and stops provided to limit movement of the blade. - 6-

Claims

1. A cooking vessel in which a rotary agitator is provided to stir or agitate the vessel contents, the agitator being provided with a plurality of scraper blades for scraping the inner surface of the vessel, each blade being in the form of a one-piece plastics member having trunnions received in openings in a support, the trunnions and the openings in the support being shaped so as to cooperate and allow the blade a restricted amount of angular movement towards and away from the inner surface of the vessel.

2. A cooking vessel as claimed in Claim 1, wherein the blade has a bottom wall and side and end walls, the tip of the blade being constituted by the leading edge of the bottom wall.

3. A cooking vessel as claimed in Claim 2, wherein the tip of the blade is curved in plan and extends beyond the leading extremities of the side walls.

4. A cooking vessel as claimed in Claim 2 or Claim 3, wherein the side walls of the blade are substantially triangular in shape.

5. A cooking vessel as claimed in any of Claims 2 to 4, wherein the support for each scraper blade is in the form of a stirrup having a pair of limbs provided with the openings, the blade being removable by moving the arms of the stirrup apart to release the trunnions.

6. A cooking vessel as claimed in any of the Claims 2 to 5, wherein the peripheral surface of the trunnions of the blade includes oppositely facing semi-cylindrical surface portions joined by planar surface portions, the openings in the stirrup being generally rectangular in shape with curvilinear corners.

7. A cooking vessel as claimed in Claim 1, wherein each blade has a bottom wall, an end wall and a pair of oppositely disposed side walls, the side walls being formed with the trunnions and the inner surface of the bottom wall meeting the end and side walls by way of concavely curved transition surfaces, the leading edge of the bottom wall serving as the tip of the scraper for contact with the vessel surface, the blade being shaped to 7- guide food product away from a surface being scraped.

8. A cooking vessel as claimed in any of Claims 2 to 7, wherein the leading edge of the bottom wall of the blade has a sharp-edged tip for engagement with the bowl of the vessel, the tip being arranged to wear in such a way as to retain a sharp edge.

9. A cooking vessel as claimed in claim 1, wherein the blade has a bottom wall and at least an end wall, the leading edge of the bottom wall forming a scraper tip, the bottom wall meeting the end wall in a concavely curved surface.

10. A cooking vessel as claimed in Claim 1, wherein the blade is of dished or shovel- like from.

11. A scraper blade for a rotary agitator of a cooking vessel comprising a one-piece plastics member having a bottom wall, an end wall and a pair of oppositely disposed side walls, the side walls being formed with trunnions and the inner surface of the bottom wall meeting the end and side walls by way of concavely curved transition surfaces, the leading edge of the bottom wall serving as the tip of the scraper for contact with the vessel surface, the blade being shaped to guide food product away from a surface being scraped.

12. A cooking vessel incorporating scraper blades substantially as hereinafter described with reference to and as illustrated in the drawings.